How To Fix Air In Fuel Lines On Your Outboard Motor

[@SkilltradeMarketing]

When you press wound the air pressure your creating vent out the vent? It's not a closed system because it's vented

[@jaredrhodes7288]

Very practical and helpful video. Thank you

[@jayvette75]

3 MONTHS I have been causing this PROBLEM THANK YOU !!!!! I replace 2 carbs and had the same problem and now I know why . I changed the fuel sending unit and ever since I have had problems.. %$%@&%^@)(I))!%^$^@^% AIR IN THE LINES !!!!! I am so happy I saw this. I made 20 post on a boat forums NO ONE EVER came up with this WTF !!!!! ' THANK YOU AUSTIN!!!!!!!!

[@fishingwithaustin8258]

Always start with your fuel system, work one end, to the rear, then use a separate fuel tank , always start cheapest. TROUBLESHOOT TROUBLESHOOT TROUBLESHOOT before buying new parts, I’m so happy and thankful you fixed your problem, thank you for watching

[@stancreech43]

Man you do your own homework but I only use black line. My mechanic retired from mercury and showed me where the factory plastic type line was like sand. I’m going to put in line on/ off and I have a small filter between the tank and primer bulb. Thank you and God bless

[@fishingwithaustin8258]

I always went with blue but did the clear plastic for this test

[@JoseLara-bv2oj]

Great video brother

[@fishingwithaustin8258]

Thank you so much for watching

[@morroccomtayamo6530]

Am having trouble with air bubbles in my Diesel filters - pliz help

[@fishingwithaustin8258]

Can you explain the problem

[@bouldernelsonbigfoot]

Great Vid. i have same issue .Used permatex fuel resistant tread sealer ,bad idea. Sealer ended up in Water Serparator.

[@fishingwithaustin8258]

Oh Jesus that’s tough atleast the separator caught it before it went into the motor

[@bh5094]

How would a leaky fuel sending unit gasket cause the engine to run bad? I mean the tank is vented. Wouldn’t that gasket leaking air just be the same as another tank vent?

[@fishingwithaustin8258]

Too much air isn’t good either

[@bh5094]

@@fishingwithaustin8258 i just resealed my sending unit the other day. I’ve been having problems with my engine bogging down as well. I will take it out Friday and see if the problem is fixed. I really don’t see how it could be but I hope you are right. Either way thanks for the video. Good info

[@fishingwithaustin8258]

@@bh5094 the thing is there’s a pick up tube, no air needs to go through that. Air needs to come into the tank so it doesn’t implode. When the tank empties it needs to fill with air so the tank doesn’t suck itself inwards

[@bh5094]

@@fishingwithaustin8258Austin I was very skeptical about the sending unit gasket leaking causing my engine to big down and eventually run like crap. In my thinking the gas tank is vented anyway so how could this sending unit gasket cause this problem. I drained my VST and noticed large bubbles of air in the clear tygon tubing drain line. I pressure tested my tank and found a substantial air leak at the sending unit gasket. I replaced the gasket and was pleasantly surprised. The engine runs perfectly! I don’t understand why or how this caused the problem but it obviously did. I want to thank you for this tip and want to apologize for doubting you. Thank you!

[@bh5094]

Did it fix the problem?

[@drewramsey7255]

Thanks, great video!

[@fishingwithaustin8258]

I hope this helped you!

[@Timbuctoo]

Got a Merc Optimax 150 and took it out twice, ran well. Third time as soon as I opened up the throttle it would stall. Idles well and starts fine, just stalls and won't go above 4 mph. I think it's a fuel line issue, but not sure. Was your outboard doing this?

[@fishingwithaustin8258]

@@Timbuctoo yes I would floor it and it wouldn’t go past a certain rpm. Check for air then check filter o rings

[@richardhearn4201]

Is it dirty carbs? I had that problem, same symptoms

[@karlkoops2142]

So if you see air in the clear filter bowl in the engine area that’s a problem?

[@fishingwithaustin8258]

@@karlkoops2142 if you prime your bulb and have fuel leaking out of it from the fuel pressure yes it’s an issue

[@ericjockers3045]

Hey man, when your engine bogged down did you prime the bulb and it did the engine maintain rpm/speed? I have a similar issue and have down everything but fueling lines.

[@fishingwithaustin8258]

Your engine can maintain a certain speed or rpm when there’s air in the fuel lines because it can supply fuel up until a certain limit where fuel air ratio tops out before imbalance from too much air. If it’s a four stroke, have you tried the fuel injectors? Just replaced mine and a quick way to diagnose them is a short I uploaded on my channel

[@ericjockers3045]

Hey Austin. I found you on IG and sent you a video of the symptoms. But I think I fixed it today following this video. I replaced the lines from Tank to F/W separator (also took out the fittings cleaned them, applied better tape around threads and tightened them down good), replaced the line from F/W separator to priming bulb and from priming bulb to inline fuel filter; bypassed this line out of the rigging tube because I keep boat on water. Ran like a champ. Fingers crossed that’s all it is. Pulling the boat out tomorrow to properly replace the line. Hit me up on IG and appreciate your service!

[@FishinFool70]

Fuel sender gasket is not going to get air in the fuel line. You more then likely were getting air through that corroded up fuel line fitting on the tank. Should have changed that.

[@fishingwithaustin8258]

The gasket had a lump in it where it was leaking air, I took it off and cleaned all the build up off of it and put it back and it became flush after tightening the fasteners on it, for that situation it was the gasket

[@fishingwithaustin8258]

Also love that username

[@CADwaterfowler]

@@fishingwithaustin8258 Hi Austin, I am thinking the same thing as FTW688. The sending unit gasket is above the fuel LEVEL line. The fuel pick up is submerged in the fuel so the air leak would have to be in theory somewhere between the pick up to the motor. There are a lot of sources where air is exposed to the system before it hits the tank, for example the fill cap is not 100% sealed, the vent....well that's self explanatory. As far as I know there is no back flow prevention valves from the vent to the tank. So with those 2 examples I can't see how a small leak in the sending unit gasket would allow air in the fuel lines with the pick up being submerged in the fuel, Are you following me? I am going through the same thing you are right now with my 2011 115 Yamaha, its driving me crazy. I have changed everything and still the same issue. Only thing I have not done is replaced or bypassed the water separator. When I hook up an external take it will reach full RPM and works like a charm. Clearly sucking air from somewhere. BUT WHERE!!!!!

[@labernese]

Exactly, if the vent is functioning properly you will not create a vacuum in the tank as fuel is consumed. If the vent is blocked and even a small vacuum is formed air will find a way into the suction side of the system downstream of the tank.

[@robbyddurham1624]

I agree with the other guys about the seal around the sending unit and that it might have been the elbow fitting. I'm having the same problem and I'm pretty sure the problem is in from of the ball pump and might be the same fitting on mine. I don't think the gas caps are sealed or the vent isn't sealed, so the problem has to be in the fuel line somewhere between where the pick up is above the fuel level. Oh, mine eventually seals up and works all day after I keep the fuel pumped up for about 15 minutes while running. I can see the air bubbles moving in the clear tube I added in from of the ball pump.